The comments were made after South Korean officials returned from a visit to the North, where they met with North Korean leader Kim Jong Un.

South Korea says North Korea has agreed to impose a moratorium on tests of nuclear weapons and missiles if it holds talks with the United States.

South Korea's presidential national security director said Tuesday that North Korea said it's ready to have "heart-to-heart" talks with the United States on issues regarding the North's potential denuclearisation and the normalisation of relations between Pyongyang and Washington.

He said the North also made it clear that it wouldn't need to keep its nuclear weapons if military threats against the country are resolved and it receives a security guarantee.

He said the North also promised not to use conventional or nuclear weapons against South Korea.

The comments were made after South Korean officials returned from a visit to the North, where they met with North Korean leader Kim Jong Un.

South Korea's presidential office also said Tuesday that the countries have agreed to set up a telephone hotline between their leaders.

South Korea's presidential national security director, Chung Eui-yong, said North Korea has also made it clear that it wouldn't need to keep its nuclear weapons if military threats against the country are resolved and it receives a credible security guarantee.

The comments were made hours after a South Korean delegation led by Chung returned from a visit to the North, where they met with North Korean leader Kim Jong Un.

South Korean presidential envoys have returned home a day after they met North Korean leader Kim Jong Un in a rare visit to the North.

The South Korean delegation led by national security director Chung Eui-yong was expected to head straight to Seoul's presidential palace to report to President Moon Jae-in.

Moon's office is expected to hold a media briefing on the outcome of the visit later Tuesday.

North Korean state media said the North and South Korean officials discussed a possible summit between Kim and Moon during a meeting and dinner hosted by Kim on Monday in Pyongyang.

The rival Koreas have been taking steps to repair ties strained by North Korean nuclear weapons and missile tests after the North reached out to the South over the recently concluded Pyeongchang Olympics.